Summary Two aircraft were level at flight level 350 (FL350) on reciprocal tracks approximately 23 nautical miles (nm) southeast of Sydney, Nova Scotia. Continental Airlines flight18 (COA18), a Boeing 767-400, was eastbound en route from Newark, New Jersey, USA, to Gatwick, United Kingdom. Iberia Airlines flight 6283 (IBE6283), a Boeing 767-300, was westbound en route from Barcelona, Spain, to John F. Kennedy International Airport, New York, USA. When the two aircraft had closed to approximately 10nm, both aircraft responded to traffic alert and collision-avoidance system resolution advisories. COA18 climbed to FL354 and IBE6283 descended to FL335. At the point of passing, the aircraft had achieved 1900feet vertical spacing with about 0.4nm lateral separation. The aircraft were operating in an area where the separation required was either 1000feet vertically or 5nm laterally. Ce rapport est galement disponible en franais. Other Factual Information COA18 had been cleared at flight level (FL) 330 through Moncton and Gander Area Control Centre (ACC) controlled airspace on an eastbound route from TUSKY intersection to Torbay VOR (very high frequency omnidirectional RADIO range) navigation aid before entering oceanic airspace. (seeFigure1.) When the Moncton ACC controller solicited a ride report from COA18, the crew advised that they were experiencing continuous light turbulence (chop). Ten minutes later, COA18 advised that the flight was now in continuous light chop, with occasional moderate chop. Based on previous reports of a smoother ride at FL350, the controller offered that altitude to COA18 with a turn off course to accommodate traffic. COA18 requested to maintain its present course at FL330 until clear of conflicting traffic. At 1339:03 Newfoundland standard time (NST)1 the Moncton ACC controller cleared COA18 to climb to FL350. The change in altitude was not passed to Gander ACC immediately, nor did the Gander/Moncton Agreement specifically require controllers to do so. FL350 was not an appropriate altitude for the direction of flight. Controllers use the term wrong way for internal communications with other air traffic control (ATC) sectors to describe this situation. At 1351:46, COA18 was verbally handed off from Moncton to Gander ACC control. The Moncton ACC controller advised the Gander ACC controller of the aircraft's flight level (FL350), the fact that it was a wrong-way altitude, and that the flight level was assigned because of turbulence. COA18 checked in on the Gander domestic high west (sector'C') controller's frequency at 1352:25. Six minutes before accepting COA18 at FL350, the Gander high west controller had accepted an electronic handoff from the Gander high east sector on IBE6283. IBE6283 had been cleared to fly through Gander and Moncton controlled airspace via Torbay direct to TUSKY intersection at FL350. The domestic high west specialty of Gander ACC can be divided into several sectors to efficiently accommodate expected traffic flows. The controller initially responsible for COA18, IBE6283, and three other aircraft was controlling high west sector'C', which is the airspace at the south end of the high west specialty. High west sector'A' was immediately to the north of high west sector'C'. At approximately 1403, the high west supervisor approved the consolidation of sectors'A' and'C'. This required the sector'A' controller to physically move to the sector'C' position. The sector'A' controller moved to the sector'C' position, put his flight progress strip (FPS) tray into the board, unplugged the headset of the sector'C' controller, and plugged in his own headset. A short handover briefing ensued, in which the sector'C' controller indicated that COA18 had oceanic clearance. There was no mention of the conflict between COA18 and IBE6283. The relieved sector'C' controller then left the operations room to start his break. At 1406:35, COA18 reported traffic straight ahead to the combined sector 'A/C' controller. Eight seconds later, IBE6283 advised that they were in descent out of FL350. The sector 'A/C' controller did not immediately respond to these communications. He was not expecting a call from either COA18 or IBE6283. Since he thought the two aircraft were not in conflict, he did not comprehend the reference to a deviation. The aircrew made no reference that they were initiating avoidance action as a result of a traffic alert and collision-avoidance system (TCAS) resolution advisory (RA). Recorded radar information indicated that IBE6283 started a descent at 1406:47 and COA18 started to climb at 1406:52. Five seconds later, the altitude readouts for the two aircraft indicated they were vertically separated by 700feet and increasing. At the point of closest horizontal approach, the two aircraft had achieved 1900feet vertical spacing. Neither aircrew stated initially that the evasive action was as a result of a TCAS RA. Aeronautical information and ATC manuals in Canada and the United States provide accepted standard phraseology when aircrew respond to a TCAS RA. The recommended phraseology is (callsign) TCAS climb or (callsign) TCAS descend. At 1407:05, after the aircraft had passed each other, the crew of IBE6283 advised that they had descended out of FL350 because of a TCAS alert that had indicated traffic straight ahead at FL350. The crew of COA18 then informed the controller that they had initiated a climb as a result of a TCAS alert. The sky was clear above cloud, and each aircrew saw the other aircraft after the TCAS RA. IBE6283, as well as descending, commenced a shallow right turn to ensure continued separation between the two aircraft. The peak descent rate achieved by IBE6283 during the TCAS RA manoeuvre was 6000 feet per minute, and the aircraft descended to FL334 before levelling off. Both aircraft were subsequently cleared back to FL350. Handover briefing checklists were available at each control position in the Gander domestic high specialty. Nav Canada's Air Traffic Control Manual of Operations (ATCMANOPS) specifies that the relieving controller is to peruse the checklist before the handover briefing. However, instructions do not require the controller to directly refer to the checklist during the briefing. Neither controller referred to the checklist before or during the briefing, nor were they in the habit of doing so. One of the items on the handover checklist refers to traffic information such as possible/probable separation problems. ATC MANOPS states that a controller shall remain behind for monitoring purposes jointly with the relieving controller to reinforce the position relief briefing and assist the relieving controller in becoming familiarized with the position. However, the post-relief overlap time requirement shall be based on traffic volume and complexity. Each controller is responsible to exercise the best judgment possible in evaluating the situation and taking the appropriate time to effect a complete exchange of information. Both controllers felt that the handover briefing had been adequate because there was little traffic and, therefore, no need to discuss each flight in detail or for the relieved controller to remain behind to monitor. Upon assuming responsibility for the sector, the new sector 'A/C' controller spent the next few minutes setting up the radar situational display (RSiT) to his liking. He did not complete a detailed scan of the flight data board nor did he compare the information on the FPS with that displayed on the radar. The sector 'A/C' controller was not aware, until the call from COA18 about traffic ahead, that there was a conflict that required action on his part to resolve. The sector'C' controller had began his shift that day at 0830 and had been controlling in the high west sector'C' for the previous 60minutes. The sector'A/C' controller had taken over control of sector'A' at 1352, a few minutes before the consolidation with sector'C'. His shift had started that day at 1100. The traffic level was light. No data controller was assigned to sector'A' or'C'. ATC procedures are very specific on the type of information that must be included on FPSs. This includes marks to indicate confirmation of altitude on initial contact, clearances issued and confirmed, wrong-way altitudes, and potential conflicts with other aircraft. ATC MANOPS specifies that a wrong-way altitude is to be circled in red on the FPS. For operational reasons, the approved local procedure at Gander ACC is to print'WW' on the altitude block of the FPS. The sector'C' controller did not mark the FPS to indicate that COA18 was flying at an altitude inappropriate for the direction of flight. ATC MANOPS also specifies that when conflicting traffic exists, the flight number for the conflicting traffic is to be entered on the FPS. The sector'C' controller's normal practice was to not mark FPS for conflicts or wrong-way altitudes that would be solved before handing the aircraft to another sector or ACC. The sector'C' controller did not mark the FPS to indicate conflicting traffic for COA18. The sector'C' controller had not used any of the available radar display tools to highlight either or both of these aircraft as a reminder that further action would be necessary to ensure separation. Radar, where available, has become the primary system used by controllers to control traffic and to identify conflicts; however, there are no published standard procedures that require controllers to use specific display tools to highlight potential problems or otherwise serve as a memory aid for the controller. On 31 August 2000, the TSB recommended (A00-15) that Nav Canada commit, with a set date, to the installation and the operation of an automated conflict prediction and alerting system at the nation's ATC facilities to reduce the risk of midair collisions. Nav Canada began testing of an ATC conflict-alert system on 31March2001 at the Toronto ACC; however, testing has since been interrupted because of technical difficulties. Transport Canada is monitoring this testing.